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<Paper uid="W04-1306">
  <Title>On the Acquisition of Phonological Representations</Title>
  <Section position="6" start_page="46" end_page="46" type="concl">
    <SectionTitle>
6 Conclusion
</SectionTitle>
    <Paragraph position="0"> I will conclude by raising one further problem for learning models that is suggested by the Manchu vowel system. We have observed that in Classical Manchu, / / is the [+ATR] counterpart of /a/. Both vowels are [+low]. Since [low] is ordered first among the vowel features in the Manchu hierarchy, we might suppose that learners determine which vowels are [+low] and which are not at an early stage in the process, before assigning the other features. However, a vowel that is phonetically [ ] is ambiguous as to its featural classification. In many languages, including descendants of Classical Manchu (Zhang, 1996, Dresher &amp; Zhang, 2003) such vowels are classified as [ low]. What helps to place / / as a [+low] vowel in Classical Manchu is the knowledge that it is the [+ATR] counterpart of /a/. That is, in order to assign the feature [+low] to / /, it helps to know that it is [+ATR]. But, by hypothesis, [low] is assigned before [ATR]. Similarly, the determination that /i/ is contrastively [+coronal] is tied in with its not being contrastively [ labial]; but [coronal] is assigned prior to [labial].</Paragraph>
    <Paragraph position="1"> It appears, then, that whatever order we choose to assign features, it is necessary to have some advance knowledge about classification with respect to features ordered later. Perhaps this paradox is only apparent. However it is resolved, the issue raises an interesting problem for models of acquisition.</Paragraph>
  </Section>
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